I use Bulwark on my entire lance. With 3 Gun & 1 Tactics specialists. This has been working really well, since I have gotten big enough mechs to take some punishment. I sneak around the edge of the board and find high ground. Then I let the bad guys come to me. If the don''t show up in a half dozen or so turns I sent my tactics guy out to find them & lure them back to me. Usually, I can kill the first few fast ones as they show up one or two at a time. After that it's just concentration of fire until an enemy goes down. I use LRMs, PPCs & AC2-10s on all my mechs. I believe in doing unto others BEFORE, they do unto me.

In my last playthrough all my mechwarriors used Guts and Tactics. First goal was to reach Guts 5 to get Bulwark, then to reach Tactics 10. Went for LRMs and Medium Lasers. Had no problems.

Dislike Gun, it is better to destroy 1 enemy mech, than to have 3 light damaged enemies who are shooting at my mechs.

Currently Bulwark is one of the most usefull skills. It essentialy doubles your hp. But I wouldn't discard multishot and breaching shot. Against entranched enemies you can shoot up to 3 enemies for full damage with that (and hitting head for 50dmg instead of 100dmg with ac/20 makes the differance).
And take into account that the game itself will change. Currently damage/heat is not consistent with tabletop and this unbalance many things (and there is community pressure to make the game as tabletop as possible). Also currently game favours close range weapons due to limited view range. In tabletop only line of sight limist your aim. When they will restore bonuses/penalties to view ranges and radar ranges for mech classess it will change everything.
On nexusmods there is a mod cbt rebalance which aims to give tabletop experience (correct damage, heat, speed etc.)

I use two Lancers and two Vanguards. All have Bulwark. Lancers have two Gunnery skills. Vanguard have two Tactics skills.