Not too fast, not too slow...and not to be too selective also.
Did u knows why US Army took so many shit years, months and days but just couldnt totally invaded vietnam???
1) Fcuking Thick Terrain
2) Super IQ by viet commander
3) Super viet con tunnel
4) Super hot weather too....
Enough for de Americians to handle lor...
Learn by hard was to prepare de next battle...
Almost de same tactics that could be apply on vietnamese...but takes time...