For fall '89 and spring '90, the band hired state of the art remote recording truck, Le' Mobile. Each show was recorded in multitrack. The best selections are what made up 'Without a Net'. These recordings sound so good due to both the way they were recorded and all of the work done afterwards; overdubbing, mixing, mastering, etc.
As for what you are calling 'official recording methods', Healy started recording digitally on 12/27/82. These recordings were stereo to Beta PCM cassettes (remember the Betamax?) which a select few cutting edge tapers had been using for FOB recordings as well. The Alesis ADAT multi-track recordings started sometime in the later 80's (guessing '87-'88). The ADATS offered the flexibility to produce record label quality, digital recordings that could be tweaked in the studio afterwards. This made it relatively easy for the band to push out hi-quality shows; Dozin at the Knick, DP's, etc.
Recording dates for Without a Net:
"Feel Like A Stranger" recorded at Hampton Coliseum, Hampton, Virginia on October 9, 1989
"Victim or the Crime" recorded at Brendan Byrne Arena, East Rutherford, NJ on October 15, 1989
"Cassidy" recorded at The Spectrum, Philadelphia on October 19, 1989
"Bird Song" recorded at Great Western Forum, Inglewood, California on December 9, 1989
"Let It Grow" recorded at Capital Centre, Landover, Maryland on March 14, 1990
"Walkin' Blues" and "Althea" recorded at Capital Centre on March 15, 1990
"Mississippi Half-Step Uptown Toodleloo" recorded at Copps Coliseum, Hamilton, Ontario on March 21, 1990
"One More Saturday Night" recorded at Knickerbocker Arena, Albany, New York on March 24, 1990
"Looks Like Rain" recorded at Nassau Coliseum, Uniondale, New York on March 28, 1990
"Eyes of the World" recorded at Nassau Coliseum on March 29, 1990
"Help on the Way/Slipknot!/Franklin's Tower" recorded at Nassau Coliseum on March 30, 1990
"China Cat Sunflower/I Know You Rider" and "Dear Mr. Fantasy" recorded at The Omni, Atlanta on April 1, 1990