i love walls of text, im about to to post a big one, so get ready lol.
the best free reliable software you can use is OBS Classic(Open Broadcaster Software), its completely free,and depending on your settings and bitrate, it will only affect an average of 7-15% of your system performance.
heres a very simple tutorial video on how to do it.
the size per minute on videos are somewhat small unless your bitrate and quality that you set are very high.
some small common problems:
if you do start having suttering when watching your recordings, try to downscale the resolution on video and enconding options,lower the fps(this will not lower the fps in-game only the recording [take that fraps!]), or the bitrate as your pc is not beeing able to handle it very well.
you can customize the the way or videos look based on your systems performace that way,as well as disabling CBR And CBR padding(i dont know if thats a good idea, but i record my videos without it and have no problems).
if you notice that your audio is lagging out and coming only 1 or 2 seconds later,force desktop audio to use video timestamps as a base for audio time on advanced settings.
about your assault play on blocking rocks…
i suggest that you always have on you at least 2 jetpack boosts or 1, so you can dodge in the front of the rock,a common mistake would be waste the jetpack all the time to keep up with the monster which is fine, but things will go really south if the monster rock throws or focuses you.
also theres another way you can make this happen by making your focused teammate come to you, which makes rock blocking much easier, but you cant expect this to always happen as your teammate might find easier to just dodge,that he dosent trust that you will block the rock or that you are too far to block the rock.
when it comes with domes with a lot of verticallity it will depend on the assault, assaults like Markov,Blitzkov,torvald,Hyde can really punish a monster if he goes for a teammate that is roaching.
You can plant the mines on the top of the pillars, throw a toxic nade between its base and its top,you can straight out destroy a monster just by aiming up with torvald mortar.
other assaults can still make it work, but will have a bit more trouble, like parnell or lennox since their special equipment (3), dosent have any sort of area of denial, but a huge burst of damage.
r.abe well,you can just keep dotting the monster i guess…
every Assault has a way of dealing when they are beeing focused, but most of the time youll be the one relying on your defense matrix, and your team, if the monster focuses you, and you pop matrix, while beeing healed or shielded, you will quickly be outhealed and out shielded by the monster while taking huge punishment for it, which is why assaults are often monsters last priority of targets(with some exceptions like lennox and bltiz markov).
if the monster insists and you see that your team cant keep with the monster, make sure you have at least 1 or 2 jetpack boosts,and lure the monster to one of your special equipment in a confined place if you are markov or blitzkov(mines),hyde(toxic grenades), if you are torvald, aim the mortars towards the direction you are going (8m is the minimum remember) shoot and boost right under it,you will heavly punish the monster for focusing you(you can use this in conjuction if the team can keep up with the monster by outhealing & outsheilding the monsters damage. use this for maximum damage).
some assaults dont have these advantages, like R.abe, Lennox,parnell,Blitzkov(if he dosent have mines),so make sure you have at least 1-2 jetpack boosts so that you can rely on making a roaching , a pillar circling or pillar hopping until ur matrix is up again,or depend heavly on your team.
i recommend, blitz markov, lennox and torvald, they do a shitload of burst at once,blitz markov if you can keep the tesla gun beam until it reaches red and gold and lure the monster to your (gold mines hehe),lennox if you start getting 3x to 4x multiplier on your plasma lance + thunder strike, keep in mind that if the monster just slaps you with a melee he will reset their multipliers and will have to start all over again, same goes for blitz markov.
Torvald IF you can master him, i think he is the bursty assault in the game, but you will have to learn how to predict the monsters movement to hit em with your mortars , were talking about 175 * 6 (mortars) thats 1050 damage at once if you hit all of em(and thats with no perks!), and on a 5 second Reload time,the big issue is hitting his mortars, it takes a lot of practice and a lot of training to hit em consistently.
i hope that helped you a bit on how to improve your assault play.